The White House has revealed its plans for closing the controversial Guantanamo Bay detention facility, one of the president’s long-standing goals.The Pentagon has proposed transferring the remaining 91 detainees to their home countries or to US military or civilian prisons.But Congress is deeply opposed and expected to block the move.The prison costs $445m (£316m) to run annually and closing it was an early promise from President Barack Obama.Senior administration officials told reporters on Tuesday that closing the prison is a national security imperative.”Implementing this plan will enhance our national security by denying terrorists a powerful propaganda symbol, strengthening relationships with key allies and counterterrorism partners, and reducing costs,” said Pentagon press secretary Peter Cook in a statement.President Obama has tried for years to close Guantanamo. He and his deputies say that it hurts the reputation of the US and that militants use “the infamous orange jumpsuit”, as one senior administration official described it, as a recruiting tool.But members of Congress have baulked at Mr Obama’s plan to close the prison, saying they believe it should remain open – and they don’t want any detainees to be transferred to the US. Representative Mike Pompeo of Kansas, for example, said the prisoners should “stay right where they are”.Lately, though, White House officials said that lawmakers, or at least some of them, seem more receptive to the idea.A senior administration official told reporters that there’s “room for conversation”. That’s important since Mr Obama has less than a year to close the prison – and for him time is of the essence.